The rotor of an induction motor must always turn sufficiently faster than the rotating magnetic field so that magnetic lines of flux will cut through the rotor bars and induce a voltage.

Lines of Flux

Imaginary lines used to represent the strength and direction of a magnetic field around a magnet.

Rotor Bars

Metal bars mounted in the rotor of an induction motor, which conduct current and create a magnetic field that interacts with the stator to produce torque.

Induce Voltage

The process by which a voltage is generated in a conductor by changing the magnetic field around it.